Electronic devices often need to generate multiple power supply rails while only being powered by a single source. For example, a laptop computer may only have a single battery but may need to produce power supply rails with different voltages for the various components on the laptop. Furthermore, regardless of the need for multiple power supply rails, electronic devices often need to condition the power that is delivered to them from an external source.
Synchronous switching power converters are a particularly efficient class of power converters that meet these requirements. For a given voltage at a voltage input of the converter, a different output voltage is produced at a voltage output of the converter. The output voltage produced is determined by the relative on-time and off-time of a control switch of the converter. During the time that the control switch of the converter is turned off, a synchronous switch of the converter is turned on.
However, if both the control switch and the synchronous switch are in an ON state simultaneously, a current path between a voltage input node of the converter and a ground node of the converter is formed. This effectively shorts the voltage input node to ground. This condition is known as cross-conduction or “shoot-through” and can cause catastrophic damage to the control switch and/or the synchronous switch. As such, both the control switch and the synchronous switch are typically transitioned to an OFF state for a time interval before the complementary switch is transitioned to an ON state. This is sometimes referred to as an anti-cross conduction interval or “dead-time.” Unfortunately, while an anti-cross conduction interval is typically necessary, this interval results in inefficiencies and power loss in the converter that increase with longer anti-cross conduction interval times.